1. Field of the Invention
The present invention relates to a varistor, particularly, a varistor with a varistor element consisting primarily of ZnO (zinc oxide), and to a method of producing the varistor.
2. Related Background Art
A known varistor of this type is one provided with a varistor element and external electrodes disposed on the varistor element (e.g., cf. Japanese Patent Application Laid-Open No. 6-120007). In the varistor described in the Laid-Open No. 6-120007, the varistor element contains ZnO as a principal ingredient and contains Bi as a material to induce nonlinear current-voltage characteristics (which will be referred to hereinafter as “varistor characteristics”).
The Laid-Open No. 6-120007 discloses the following method of producing the varistor. The method includes the first step of laminating ceramic green sheets each with a conductor pattern for an internal electrode and ceramic green sheets without any conductor pattern in a desired order, and the subsequent step of firing them to obtain the varistor element. An electroconductive paste is applied onto the resultant varistor element body and then it is baked to form the external electrodes.